In this SBIR we propose to develop a retinal vessel oxygen saturation monitoring system for investigational and clinical use. Retinal oximetry has been the subject of intense research and development since Hickam et al published the first photographic means in 1963. Studies of the retinal circulation and oxygen saturation have implicated oxygen status in diseases of the retina, including vein occlusion, diabetic retinopathy, glaucoma and optic atrophy. Oximetry studies have shown impairment of retinal blood flow regulation in diabetes and improvement in retinal oxygenation by pan-retinal photocoagulation treatment for proliferative diabetic retinopathy. Recently, studies have used imaging oximetry technique to evaluate side effects of glaucoma medications on retinal oxygenation. Thus, there is growing interest in retinal oximetry for monitoring retinal pathology. We propose here to develop an instrument we call OXYCAM for determining changes in oxygenation from distinct regions of the retina. This ability to detect subtle changes will be important in preventing the blinding complications of retinovascular disease. The long-term objectives of this project are 1) to make available a standardized commercial system for oximetric evaluation of retinal disease in research institutions and clinics and 2) to determine the role of oximetry as a retinal evaluation tool, which will lead to a commercial market for oximetry products. The specific aims of Phase I include 1) development of the dual-wavelength OXYCAM Imaging system for oximetric assessment at different levels of the retinal circulation and 2) validation of the OXYCAM performance in normal subjects. Coverage of retinal vessel networks in single dual-wavelength recordings will be achieved with pairs of large-format CCD sensors and a dichroic image splitter. Our longer term aims in Phase II include 1) development of automated vessel tracking and oximetry analysis software, 2) refinement of oximetry technique to improve accuracy and reproducibility in clinical work and 3) multi-site investigations into the role of oximetry in diagnosis, management and treatment of retinal disease.